Drums of 55-60 gallon capacity are generally provided in two forms, known in the trade as tight head drums and open head drums. In a tight head drum, the top and bottom covers are secured by chimes in sealing relation with the top and bottom of the barrel of the drums. Access for filling the drum with liquid is usually through a plugged opening through the top while the liquid content material is removed through a smaller plugged bung hole in the top or in the side wall of the drum. In an open head drum, use is made of a removable cover, having a peripheral looped portion that fits over a curl in the upper edge of the drum, and the cover is secured in a position of use to seal the open end of the drum by a removable locking ring which fits about the interfitting loop and curl to secure the elements in their assembled relation. The content material is introduced through the open end of the drum before the cover is secured and the content material is removed through the open end of the drum after the cover has been removed.
By reason of the means for closure of tight head drums, and by reason of the inaccessibility to the interior of the drum for cleaning without removal of the end closure, tight head drums do not enjoy the economy of reuse. Removal of the cover for cleaning the interior requires reconstruction of the end closure system for reuse, and this at considerable expense.